(HOW TO) add meta tags, basic seo for blog posts

How does I perform basic seo functions for posts on a blog such as meta tags, image alt text tags, etc? My blog is not showing up on key word searches that our specific to the industry and would like a better understanding as to how i can do so. I am not html savvy, but i can do research to execute. I would like a better understanding of how to begin this process.

Thanks.